Passivation profiles depth

Figure 15 shows the time development of a typical passivation profile (Seager and Anderson, 1988). The integral, from any depth x to infinity, of the amount by which the curve for any given time falls below the asymp-... 

Fig. 3.22. Depth profile of a passivation layer on high-purity chromium. The 0 layer is on the top, the 0 layer at the interface with the metal.

According to the depth profile of lithium passivated in LiAsF6 / dimethoxyethane (DME), the SEI has a bilayer structure containing lithium methoxide, LiOH, Li20, and LiF [21]. The oxide-hydroxide layer is close to the lithium surface and there are solvent-reduction species in the outer part of the film. The thickness of the surface film formed on lithium freshly immersed in LiAsF /DME solutions is of the order of 100 A. 

A comparison of the deuterium profile measured by SIMS and the spreading resistance profile obtained on deuterated samples is shown in Fig. 6. The region over which there is a reduction in thermal donor concentration matches well with the depth of deuterium incorporation. There is an excess of deuterium over the amount needed to passivate all the oxygen-donor centers. This is frequently observed in hydrogenation experiments and indicates there is hydrogen present in several states. 

Fig. 8. SIMS profiles of 2H and nB in plasma-passivated B-implanted and annealed samples used in channeling studies of B—H complexes by Marwick et al. (1988). 1000 angstroms was etched off the surface of this sample to eliminate a layer containing a large excess of hydrogen. Nevertheless, some excess over the boron concentration remains at shallow depths. The histogram shows the deuterium profile used to analyze the data using calculated flux profiles.

Fig. 17. Advance of a passivated region into silicon uniformly doped with 5 x 1018 boron atoms per cm3, after exposure for 30 min. at about 150°C to atomic deuterium from a plasma source (Johnson, 1985a). (a) Spreading resistance profile, (b) Depth distribution of total deuterium and of boron from SIMS.

Chlorosilane deposition imparts no basicity (Fig. 6C) and no acidity (Fig 5C) its only effect is to passivate the glass substrate partially. Carbon and chlorine concentration profiles that increase with penetration depth suggest an inverted orientation with the silicon atom uppermost (Table 1) bonded as siloxane (Table 3), seemingly a prospect for enhanced surface acidity, but not evinced by PTD measurements. 

The 14C content of SOM decreases with depth in the soil profile (Martin et al., 1990). An estimate of the passive pool could be obtained by measurements of the 14C of SOM in deeper layers (Harrison and Broecker, 1993). Physical fractionation and sequential extraction have also been used, and they have shown progressively lower 14C/12C ratios in decomposing residues. 

Fig. 12.58. XPS atomic concentration profile of the passive film of Al alloys as a function of sputtering depth (a)...

Fig. 12.60. 3D-XPS depth profile of passive film formed on Al for pH 8.4, at V= 0.4 V for 1 hr distribution of two different O species (as indicated) before the breakdown occurred. (Reprinted from J. O M. Bockris and L. Minevski, J. Electroanal. Chem. 349 388, copyright 1993, with permission from Elsevier Science.)...

The intensities of the integrated signals may be evaluated on the basis of well-characterized standards. Consequently ISS provides qualitative and quantitative information on the composition of the surface. Noble gas ions that penetrate the first layers of the surface are backscattered as neutrals, and thus may not pass the energy analyzer. As a consequence, only ions backscattered at the first atomic layer are detected and the method is sampling the outmost atomic layer. A soft sputter process by noble gas ions yields an ISS depth profile with atomic depth resolution. Therefore ISS has been applied to the study of very thin oxide films, as e.g. of passivated Fe/Cr alloys. This method may be applied in addition to XPS due to its high depth resolution. 

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